Detergent composition in solid form containing a synergistic mixture of cmc and pvp



United States Patent 3,318,316 DETERGENT COMPOSITION 1N SOLID FORM CUNTAINKNG A SYNERGifiTlC MIXTURE 0F CMC AND PVP James Rutherford Trowbridge, Westfieid, N.J., assignor to Colgate-Palmolive Company, New York, N.Y., a corporation of Delaware No Drawing. Filed Nov. 12, 1964, Ser. No. 410,721 5 Claims. (Cl. 252-137) The present application is a continuation-in-part of my application S.N. 783,712 filed Dec. 30, 1958, now abandoned. The present invention relates to a detergent composition comprising a water-soluble higher alkyl benzene sulfonate detergent and a mixture of soil-suspending agents which results in enhanced soil suspension in a washing solution, said mixture comprising a watersoluble carboxymethylcellulose and a water-soluble vinyl pyrrolidone polymer, as hereinafter described and claimed.

In general, the washing efficiency of a detergent composition during laundering of soiled fabrics is the diiference between the amount of soil removed from the fabric during the washing operation and the amount re-deposited upon the fabric from suspension in the washing or detergent solution. It is known in the detergent art to prepare compositions containing an organic detergent which aids in the removal of soil and a soil-suspending or antiredeposition agent which inhibits the soil redeposition onto the fabric. A large variety of chemical materials have been proposed as soil-suspending agents including polyvinylpyrrolidone, a-crylamide polymers, natural gums, carbohydrates, protein materials, and cellulose derivatives such as carboxymethylcellulose.

In accordance with the present invention, it has been discovered that a detergent composition comprising in combination a water-soluble higher alkyl benzene sulfonate detergent and a mixture of a water-soluble carboxymethylcellulose soil-suspending agent and a water-soluble vinyl pyrrolidone polymeric soil-suspending agent, the proportions thereof being effective in combination as more particularly described hereinafter, exhibits an enhanced degree of soil suspension, particularly during washing of white cotton fabrics in the presence of carbonaceous material. A synergistic improvement in soil suspension is achieved by this combination of soil-suspending agents with said detergent as evidenced by a superior whiteness of the washed cottons as compared to the expected effects for said mixtures. The expected value for any mixture can be calculated by averaging or summing the two independent effects resulting from the use of these agents individually. The reference to the Watersoluble soil-suspending agents or similar expression is intended to refer to their solubility or dispersibility in aqueous detergent solutions and the property of these materials for inhibiting the deposition of soil from a detergent solution upon the fabric and is not limited to any specific mechanism for producing such effect. Various preferred embodiments thereof will be apparent from the following description.

As indicated, the watersoluble carboxymethylcellw lose material is a known soil-suspending agent which is usually an alkali metal salt thereof such as the sodium and potassium salts. Sodium carboxymethylcellulose and the like are available usually in form of powders, in various grades of purity and viscosity in solution. The commercial grades of sodium carboxymethylcellulose having a purity from about 60 to 100% on a dry basis and which are of low, medium or high viscosity may be employed. It is preferred to employ such cellulosic salts having a viscosity from about to 1,000 centipoises in a 2% concentration in water. The degree of substitution of the carboxymethyl group per anhydroglucose unit in the cellulose molecule is variable, but is usually from about 0.5 to 2, and preferably up to 1.25 substitution.

The soil-suspending agent used in combination therewith is .a water-soluble vinyl pyrrolidone polymeric material. The specific or exact degree of polymerization is not critical provided the material has the desired watersolubility and soil-suspending power since the material is usually a mixture of specific polymers containing a different number of monomer units, depending upon the manner and degree of polymerization. In general, these suitable soil-suspending pyrrolidone polymers are linear in structure and have an average molecular weight usually within the range of about 5,000 to about 100,000, and preferably from about 15,000 to about 40,000. In general, these materials have an amide linkage and are considered to be non-electrolytes, such as the high molecular Weight polymers of N-vinyl pyrrolidone which are soluble in water colloidally. Examples of specific suitable vinyl pyrrolidone polymers are those having an average molecular weight of about 15,000; 20,000; 30,000; 40,- 000; 80,000; and 100,000.

A Water-soluble higher alkyl benzene sulfonate should be employed in admixture with the specified combination of soil-suspending agents. In combination, this detergent enables the effective removal of soil from the fabric in the washing bath and complements the action of the soil-suspending agents which is directed to inhibiting redeposition of the soil upon the fabric so as to produce the enhanced effects. Such detersive materials are known and have sufficient Water-solubility or dispersibility to form detersive aqueous solutions in the concentrations which are suitable for use such as in the washing of cotton fabrics and the like. These detergents may be used individually or in any desired combination with others as desired provided the desired properties are not substantially adversely affected.

More particularly, the higher alkyl benzene sulfonate detergent has generally an average of about 8 to 15 carbon atoms in the alkyl group. The higher alkyl substituent on the aromatic nucleus may he branched or straight chained in structure. Examples of branched-chain groups are nonyl, dodecyl and pentadecyl groups and mixtures thereof derived from polymers of lower monoolefins such as polypropylene. Examples of straight-chain groups are n-decyl, dodecyl, keryl, tridecyl, and the like.

These sulfonate detergents are used in the form of their water-soluble salts, such as the alkali metal and nitrogencontaining, e.g. lower alkylolamine, salts. Examples are the sodium, potassium, ammonium, isopropanolamine, mono-, di, and tri-ethanolamine salts of said higher alkyl benzene sulfonate. In heavy-duty detergent compositions contemplated primarily for laundering purposes, it is preferred to use the alkali metal salts of said detergents.

The proportions of the organic detergent and the mixed soil-suspending agents in the final composition are variable depending upon the physical nature of the composition and the properties desired other than the improved detergency. Broadly, the invention is not limited to any particular physical form of the composition. It is preferably prepared in suitable solid form. It is a feature that the ingredients are to be admixed so as to form a substantially homogeneous product in solid form. Any suitable method may be employed including' mechanical blending of the ingredients to produce a uniform mixture. It is preferred to prepare heat-treated solidified compositions in particulate form such as obtained by spray-drying or drum-drying an aqueous mixture of the ingredients in known manner.

In general, the amount of the combined soil-suspending agents should be a minor proportion of the composition, e.g. 0.1 to 50% by weight of total detergent solids. The amount of detergent is at least equal to the combined soil-suspending agents, and the ratio will be selected usually from the range of about 1:1 to 500:1 parts by weight, usually at least about 2:1 and preferably from about 10:1 to 100:1 parts for optimum effects in detergent efficiency depending on various considerations such as the type of detergent composition and effects desired. The ratio of the carboxymethylcellulose salt to the water-soluble vinyl pyrrolidone polymer is generally selected from the range of about 100:1 to 1: 100 by weight and suflicient to exert the desired increase in soil-suspending power, and preferably from about 10:1 to 1:10 by weight. In deter-gent compositions comprising water-soluble inorganic builder Salts, it is preferred that the total amount of soil-suspending agents in the composition be within the range of 0.1 to 5%, preferably up to 2% whereby each is from about 0.05 to 1% by weight, the organic detergent being from about 5 to 50%, preferably to 40%, and the balance being primarily water-soluble inorganic builder salts, these amounts being by weight of total solids.

In the detergent compositions, it is preferred to employ water-soluble alkaline builder salts such as inorganic polyphosphate salts. Such polyphosphate materials are known and have the property of inhibiting precipitation of calcium and magnesium material in hard Water aqueous solution. The polyphosphate salts are used usually in the form of the normal or completely neutralized salts, e.g. sodium tripolyphosphate, tetra-sodium pyrophosphate, sodium hexametaphosphate and the like. The partially neutralized polyphosphate salt such as tetra-sodium tripolyphosphate may be employed also. Examples of other alkaline builder salts which may be employed in admixture with the detergent and soil-suspending agents are the sodium ortho-phosphates (e.g. tri-sodium phosphate), borax, soda ash, the sodium silicates, etc. EX- amples of neutral inorganic builder salts which may be present in the composition are sodium sulfate, potassium sulfate, and sodium chloride.

The mechanisms by which the combination of soil-suspending agents function in the washing baths to inhibit the redeposition of soil upon the fabric have not been determined exactly in view of the apparent co-action of these ingredients. In general, soil-suspending agents may function in detergent baths to prevent redeposition of soil onto fabrics in substantially different ways, i.e. one agent may be primarily effective due to its activity at the surface of the fabric whereas another agent may be eifective primarily in its activity at the surface of the suspended soil particles. In the case of sodium carboxymethylcellulose or the like, this material is believed to be primarily effective in preventing deposition of soil upon cellulosic fabrics by its adsorption on the surface of the fabric. In contrast thereto, the olyvinylpyrrolidone is believed to be adsorbed to an appreciable extent on carbon soil, but is not adsorbed substantially on cotton from a detergent solution. Thus, the polyvinylpyrrolidone is much more effective in preventing the flocculation and precipitation of carbon in aqueous suspension than sodium carboxymethylcellulose. The use of a selected combination of these soil-suspending agents, in accordance with this invention, one of which is primarily effective in preventing redeposition as a result of its adsorption on the fabric in conjunction with another agent which is adsorbed primarily on the soil, results in a synergistic improvement in the prevention of soil redeposition during the washing operation.

These results are evident from a consideration of the following data and examples described hereinafter which are illustrative of the present invention and it will be understood that the invention is not limited thereto. All amounts of the various ingredients are by weight unless otherwise specified.

Example I A series of detergent baths is prepared containing 0.025% sodium dodecyl benzene sulfonate detergent (the dodecyl group being a propylene tetramer) and 0.0025 of soil-suspending material in water of 150 parts per million hardness calculated as calcium carbonate. The suspending material in one bath is sodium carboxymethyl cellulose (Du Pont Grade 10 D) polyvinylpyrrolidone (GAF Grade K-20) having an average molecular weight of about 15,000 is used as the suspending material in a second bath and a third detergent bath contains a mixture of said carboxymethylcellulose and polyvinylpyrrolidone in a 1:1 ratio. Each of these detergent baths contains a suspension of 0.025% Aquadag which is an aqueous colloidal carbon dispersion as the soil.

In order to test the soil-suspending power of the above detergent solutions, a number of clean cotton test swatches are washed with one liter of each of these detergent solutions for 20 minutes at 120 F. for each determination in a Terg-o-Tometer bath which is a known detergency testing apparatus. After removal from the detergent solutions, the cotton swatches are given two 3-minute rinses in distilled water and dried.

The average light reflectance of the dried swatches washed in each detergent solution is determined by a Hunter Reflectometer. In the table below, the percent reflectance listed for each detergent solution is the approximate average light reflectance of the dried swatches compared to a magnesium oxide surface considered to have reflectance as the standard. The clean swatches before washing measure about 88% reflectance. The differences in the percent reflectance in the table is a measure of the relative soil-suspending power due to the variances in the soil-suspending material listed in the table. In the absence of soil-suspending material, the clean swatches after washing and drying similarly have a reflectance of about 30%. The results of the above series of tests are as follows:

TABLE I Soil-suspending material in detergent composition: Percent reflectance (a) carboxymethylcellulose 38 (b) Polyvinylpyrrolidone 53 (c) carboxymethylcellulose and polyvinylpyrrolidone a- 63 It is apparent from the above data that a higher degree of soil-suspension is obtained using a detergent composition containing a mixture of said soil-suspending agents compared to the use of an equivalent amount of each oi the soil-suspending agents used alone. Similar synergistic effects are obtained at other concentrations of the soil-suspending material up to approximately equal proportions of said detergent and soil-suspending material. For example, repeating the above series of tests but in creasing the amount of soil-suspending material in each detergent solution to 0.0125% results in the following percent reflectance for each detergent composition.

TABLE II Soil-suspending material in detergent composition: Percent reflectance (a) carboxymethylcellulose 47 (b) Polyvinylpyrrolidone 58 (c) Carboxymethylcellulose and polyvinylpyrrolidone 73 In comparison, when the detergent to soil-suspending ratio is about 1:1 (instead of 2:1 as in the above series) by increasing the concentration of soil-suspending agents to 0.025%, the percent reflectance obtained for said mixture of polyvinylpyrrolidone and carboxymethylcellulose is about 77%.

Example 11 Following the test procedures of Example I, a similar series of tests are conducted wherein the ratio of the sodium dodecyl benzene sulfonate to the same soil-suspending agents are varied in accordance with the conditions set forth in Table III below which lists the detergent concentration, the ratio of detergent to soil-suspending (SS) agents where present, and the percent reflectance with no SS agent, the polyvinylpyrrolidone (PVP), grade K-20, alone, the sodium carboxymethylcellulose, (CMC), grade D, alone and a 1:1 mixture of these two soilsuspending agents (PVP-CMC). The total amount of The foregoing results clearly show that the soil suspending combination of polyvinylpyrrolidone and sodium carboxymethylcellulose in admixture with various proportions of sodium dodecylbenzene sulfonate gives superior results as compared to the use of an equivalent proportion of either soil-suspending agent alone with the same detergent ratio.

Example III A similar series of tests was conducted wherein each detergent bath contained 025% sodium tridecyl benzene sulfonate detergent (the tridecyl group being an average derived from propylene polymers) and 0.0025% of soilsuspending agents employed individually and in combinations as specified in the table below using various ratios of polyvinylpyrrolidone (ii-) and sodium carboxymethylcellulose (10 D) as indicated. The results obtained are as follows:

TABLE IV Soil-suspending material in detergent composition: Percent reflectance (1) No soil suspending material 30.7 (2) CMC=PVP system (percent):

This table clearly shows that with the higher alkyl benzene sulfonate said mixtures of carboxymethylcellulose and polyvinylpyrrolidone soil-suspending agents exhibit synergistic soil-suspension effects in various ratios.

Example IV A commercial detergent composition which contains about 20% sodium dodecyl benzene sulfonate (the dodecyl group being derived from a propylene tetramer), sodium tripolyphosphate, 30% sodium sulfate, 7% sodium N-silicate, and 0.5% sodium carboxymethylcellulose and small amounts of other ingredients such as perfume, optical bleaching agents and the like is dissolved in 0.1% concentration in Water of 150 ppm. hardness. The amount of carboxymethylcellulose in solution is thus .0005%. To one aliquot of this detergent solution, there is added an equal amount of sodium carboxymethylcellulose to make a total concentration of .001% anti-redeposition agent in the solution. To another aliquot portion, there is added an amount of the watersoluble polyvinylpyrrolidone (av. M.W. 15,000) equal to the amount of carboxymethylcellulose so that the total anti-redeposition material in solution is 001% also.

These detergent solutions are then subjected to the same soil-suspension tests described in Example I with the following results showing the superiority of the detergent composition containing the combination of soil-suspending agents:

TABLE V Soil-suspending material in detergent composition: Percent reflectance (a) Carboxymethylcellulose 73 (b) Carboxymethylcellulose and polyvinylpyrrolidone 77 The following examples set forth additional formulations of detergent compositions containing the combination of said soil-suspending agents using polyvinylpyrrolidone K-ZO (av. M.W. 15,000) or K-30 (av. M.W. 40,000) with the sodium carboxymethylcellulose:

Example V Ingredients: Percent Sodium dodecyl benzene sulfonate 35 Tetrasodium pyrophosphate 25 Sodium N-silicate 3 Sodium carboxymethylcellulose 0.25 Water-soluble polyvinylpyrrolidone 0.25 Sodium sulfate Balance Example VI Ingredients: Percent Sodium tridecyl benzene sulfon-ate 8 Nonyl phenol condensate with about 9.5 moles ethylene oxide 6 Sodium tripolyphosphate 40 Sodium carboxymethylcellulose 0.25 Water-soluble polyvinylpyrrolidone 0.25 Sodium sulfate Balance Example VII Ingredients: Percent Sodium dodecyl benzene sulfonate 4 Nonyl phenol condensate with about 9.5 moles ethylene oxide 10 n-Hexadecanol 1.5 Sodium tripolyphosphate 25 Soda ash 10 Aqueous sodium silicate (43.5% solids,

Na O:SiO =1:2.3) 6 Sodium carboxymethylcellulose 0.3 Water-soluble polyvinylpyrrolidone 0.3 Fluorescent dye 0.06 Sodium sulfate Balance Example VIII Ingredients: Percent Sodium dodecyl benzene sulfcnate 9 Sodium lauryl sulfate 10 Sodium tripolyphosphate 50 Tetrasodium pyrophosphate 10 Sodium carbonate 1.5 Laurie monoethanolamide 1.5 Sodium carboxymethylcellulose 0.4 Water-soluble polyvinylpyrrolidone 0.4 Sodium sulfate Balance Although the present invention has been described and illustrated with a reference to specific examples, it is understood that modifications and variations of composition and procedure are contemplated within the scope of the appended claims.

I claim:

1. A detergent composition in solid. form consisting essentially of a water-soluble alkali-metal alkyl benzene sulfonate detergent having 8 to 15 carbon atoms in said alkyl group and selected from the group consisting of sodium and potassium salts, and a mixture of soil-suspending agents of sodium carboxyrnethylcellulose and watersoluble polyvinylpyrrolidone having an average molecular weight within the range of about 15,000 to 40,000, the

ratio of said detergent to said mixture of soil-suspending agents being from about 1:1 to 200:1 by weight and the ratio of said carboxymethylcellulose to said pyrrolidone polymer being from the range of about 60:40 to :90 by weight thereof, said detergent composition exhibiting synergistic and enhanced improvement in soil suspension as compared to the use of an equivalent proportion of either soil-suspending agent alone.

2. A detergent composition in solid form consisting essentially of a water-soluble alkali-metal alkyl benzene sulfonate detergent having 8 to carbon atoms in said alkyl group and selected from the group consisting of sodium and potassium salts and a mixture of soil-suspending agents of (a) alkali metal carboxymethylcellulose selected from the group consisting of sodium and potassium salts and (b) water-soluble polyvinylpyrrolidone having an average molecular weight within the range of about 15,000 to 40,000, the ratio of said detergent to said mixture of soil-suspending agents being from about 1:1 to 200:1 by Weight and the ratio of said carboxymethylcellulose to said pyrrolidone polymer being from the range of about 60:40 to 10:90 by weight thereof, said detergent composition exhibiting synergistic and enhanced improvement in soil suspension as compared to the use of an equivalent proportion of either soil-suspending agent alone.

3. A detergent composition in solid form in accordance with claim 2 wherein the alkyl benzene sulfonate is selected from the group consisting of sodium dodecyl benzene sulfonate and sodium tridecylbenzene sulfonate.

4. A detergent composition in solid form consisting essentially of a water-soluble sodium alkyl benzene sulfonate detergent having 12 to 13 carbon atoms in said alkyl group and a mixture of soil-suspending agents of (a) sodium carboxymethylcellulose and (b) water-soluble polyvinylpyrrolidone having an average molecular weight of about 15,000, the ratio of said detergent to said mixture of soil-suspending agents being from about 1:1 to 200:1 by weight and the ratio of said carboxymethylcellulose to said pyrrolidone polymer being from the 8 range of about 60:40 to 10:90 by weight thereof, said detergent composition exhibiting synergistic and enhanced improvement in soil suspension as compared to the use of an equivalent proportion of either soil-suspending agent alone.

5. A detergent composition in solid form consisting essentially of about 5 to 'of sodium alkyl benzene sulfonate detergent having 8 to 15 carbon atoms in said alkyl group and a mixture of soil-suspending agents containing about 0.05 to 1% each of sodium carboxymethylcellulose and polyvinylpyrrolidone having an average molecular weight within the range of about 15,000 to 40,000, the ratio of said carboxymethylcellulose to said pyrrolidone polymer being from the range of :40 to 10:90 by Weight, and the balance being primarily watersoluble inorganic builder salts selected from the group consisting of sodium phosphates, sodium sulfate, sodium carbonate and sodium silicates, said amounts being by weight of the composition, said detergent composition exhibiting synergistic and enhanced improvement in soil suspension as compared to the use of an equivalent proportion of either soil-suspending agent alone.

References Cited by the Examiner UNITED STATES PATENTS 2,798,047 7/1957 Touey et al. 252152 2,981,692 4/1961 Stillo et al. 252- 3,000,830 9/1961 Pong et al. 252117 3,101,324 8/1963 WiXon 252138 3,254,028 5/1966 Wixon 252-137 OTHER REFERENCES Pong et al.: Textile Research Journal, November 1953, pp. 769-775.

LEON D. ROSDOL, Primary Examiner.

ALBERT T. MEYERS, SAMUEL H. BLECH,

Examiners. S. E. DARDEN, Assistant Examiner. 

1. A DETERGENT COMPOSITION IN SOLID FORM CONSISTING ESSENTIALLY OF A WATER-SOLUBLE ALKALI-METAL ALKY BENZENE SULFONATE DETERGENT HAVING 8 TO 15 CARBON ATOMS IN SAID ALKYL GROUP AND SELECTED FROM THE GROUP CONSISTING OF SODIUM AND POTASSIUM SALTS, AND A MIXTURE OF SOIL-SUSPENDING AGENTS OF SODIUM CARBOXYMETHYLCELLULOSE AND WATERSOLUBLE POLYVINYLPYRROLIDONE HAVING AN AVERAGE MOLECULAR WEIGHT WITHIN THE RANGE OF ABOUT 15,000 TO 40,000, THE RATIO OF SAID DETERGENT TO AID MIXTURE OF SOIL-SUSPENDING AGENTS BEING FROM ABUT 1:1 TO 200:1 BY WEIGHT AND THE RATIO OF SAID CARBOXYMETHYLCELLULOSE TO SAID PYRROLIDONE POLYMER BEING FROM THE RANGE OF ABOUT 60:40 TO 10:90 BY WEIGHT THEREOF, SAID DETERGENT COMPOSITION EXHIBITING SYNEGISTIC AND ENCHANCED IMPROVEMENT IN SOIL SUSPENSION AS COMPARED TO THE USE OF AN EQUIVALENT PROPORTION OF EITHER SOIL-SUSPENDING AGENT ALONE. 